What is dysbiosis and what are its consequences?

27th June 2022 – 3 min read

Today is World Microbiome Day, and to celebrate it, let’s shed light on some key concepts related to microbes and its impact on human health. Specifically, let’s discuss what dysbiosis means.

The microbiota refers to the community of living mutualistic microorganisms – including bacteria, archaea, viruses and fungi – that inhabit the epidermis or any cavity in a living organism. Bacteria are the most abundant, and the gut harbors the majority of these bacteria. The microbiota plays a central role in maintaining and promoting the host’s overall health across diverse physiological functions.

Dysbiosis occurs when the microbiota is disrupted or altered

Dysbiosis refers to a disruption of the homeostasis of the microbiota, which translates into an imbalance in the composition and abundance of different bacterial commensal communities (1).It results in an increase in the production of proinflammatory or other undesirable metabolites that trigger a negative relationship between the microbiota and the host.

The causes of microbiota alteration are diverse, with antibiotics use, psychological and physical stress, radiation, altered peristalsis and dietary changes being the most common factors.

The evidence linking intestinal dysbiosis to neurocognitive disease outcomes is increasing, both in the early and late stages of life. Dysbiosis in early life can be caused by antibiotic exposure, lack of breastfeeding, infection, stress, and environmental influences. On the other hand, ageing is associated with a narrowing in microbial diversity, and the gut microbiota has been implicated in a variety of conditions including depression, autism, schizophrenia, and Parkinson’s disease (2,3).

Dysbiosis is associated with onset of many diseases

Dysbiosis of the microbiota is increasingly associated with the pathogenesis of:

  1. Gastrointestinal disorders including irritable bowel syndrome, inflammatory bowel diseases, infections or diarrhea associated with antibiotics and colon cancer.
  2. Metabolic diseases such as metabolic syndrome, obesity and diabetes;
  3. Autoimmune diseases and allergies; and
  4. Neural disorders such as depression and anxiety (4)


To prevent or counteract gut dysbiosis, the International Scientific Association for Probiotics and Prebiotics (ISAPP) recommends several steps, including eating a diverse diet, exercising, and consuming probiotic foods or dietary supplements

Learn more about probiotics for specific health concerns here.


  1. Petersen C, Round JL. Defining dysbiosis and its influence on host immunity and disease. Cell Microbiol. 2014 Jul;16(7):1024-33.
  2. Levy M, Kolodziejczyk AA, Thaiss CA, Elinav E. Dysbiosis and the immune system. Nat Rev Immunol. 2017 Apr;17(4):219-232.
  3. Vangay P, Ward T, Gerber JS, Knights D. Antibiotics, pediatric dysbiosis, and disease. Cell Host Microbe. 2015 May 13;17(5):553-64.
  4. Carding S, Verbeke K, Vipond DT, Corfe BM, Owen LJ. Dysbiosis of the gut microbiota in disease, Microbial Ecology in Health and Disease, 2015; 26:1, 26191.